Only one fact is clear from Eric Cantor’s primary defeat: No one saw it coming.

This alone is a reason for skepticism about the Monday-morning quarterbacking we’re now hearing. But if college professor Dave Brat’s upset victory over the House majority leader indeed spells doom for immigration reform, Republicans and Democrats alike have some hard thinking to do about what’s ahead.

For Republican opponents of reform, the two main objections have always been lack of security at the southern border and “amnesty” — i.e., a path to citizenship for the millions here illegally.

Here’s the irony. The border is plainly broken, as we can see from the humanitarian crisis provoked by an influx of thousands of unaccompanied children that is overwhelming our folks on the ground.

But if Cantor’s defeat leads House Republicans to shy away from advancing their own plans for reform — which would begin with a bill to improve border security — what we will have for the foreseeable future is a border that remains broken, as well as a de facto amnesty for those here.

Meanwhile, Democrats who say bipartisan reform is their top priority ought to be pressing President Obama. Because any skepticism GOP primary voters might have had about the president’s commitment to enforcing the law would only have been exacerbated by seeing our border overwhelmed and our president doing nothing.

Put it this way: Is this something a president truly interested in a bipartisan immigration bill would do?
As for Eric Cantor, on this contentious issue he put forward the worst position of all for a politician: one that angered all by attempting to please all.